"It wasn't that long ago that a hotel spa would be three treatment rooms in the basement, but the bar is constantly being raised," says John Newton of Conde Nast Traveler magazine, which polls its readers annually to pick America's best spas. "Going to the spa has become a lot less about going into the hotel basement and a lot more about having a whole experience."

Newton says the best spas have 20,000 square feet or more of elaborate fireplaces, baths and treatment rooms, as well as a wide variety of physical, spiritual and nutritional programs.

Couples can enjoy spa treatments together at the Stein Eriksen Lodge in Utah.

"There are places where going in for a spa treatment also means getting a consultation about how you should be living -- what you're doing wrong in terms of cholesterol or how you need to start doing certain stretches," he says. " A spa visit can change your life if that's what you want."

And while even a basic massage can cost $100 or more at an upscale spa, Newton says that's a small price to pay for a relaxing time on your vacation.

"People on vacation can easily spend $100 on a really nice dinner -- but once you're done eating and have paid your bill, it's over," he says. "If you spend $100 on a facial or a massage at a spa, hopefully the nice feeling you get will last at least a few days. You'll be able to relax and enjoy your vacation that much more, or be more relaxed when you return home."

Here's a look at the five highest-rated facilities on Conde Nast Traveler 's latest Top U.S. Spas poll, which surveyed some 25,000 readers about their favorite spas.

Winning locations got the highest percentage of "excellent" or "very good" ratings for their facilities, staff and range of treatments.

Newton says 96.3% of respondents gave the facility an "excellent" or "very good" rating, partly because the spa's menu "reflects two increasingly popular trends --- treatments that incorporate local healing traditions ... and seasonal offerings (where) the ingredients used in treatments (are) updated throughout the year."

For instance, the Reynolds Plantation spa currently offers a $225 Spring Renewal package that features a magnolia cleansing scrub, an aloe-and-honey hydrating treatment and a magnolia-moisturizer finish.

Many of the spa's services also take their cues the region's history as the one-time home of the Oconee Creek Indians.